Bangle.js2: GPS now detects binary CASIC packets and splits them into their own GPS-raw event

Author: gfwilliams

ChangeLog

@@ -40,6 +40,7 @@
             X.on now always allocates an array - tidies up code (fix #2559)
             Bangle.js: E.showMenu no longer sends the internal `l` menu object as argument when running the callback function.
             Bangle.js2: GPS request RMC packet automatically (so GPS speed/time work even without AGPS) (fix #2354)
+            Bangle.js2: GPS now detects binary CASIC packets and splits them into their own GPS-raw event
 
      2v24 : Bangle.js2: Add 'Bangle.touchRd()', 'Bangle.touchWr()'
             Bangle.js2: After Bangle.showTestScreen, put Bangle.js into a hard off state (not soft off)

libs/banglejs/jswrap_bangle.c

@@ -587,6 +587,7 @@ JshI2CInfo i2cHRM;
 #define PRESSURE_I2C &i2cPressure
 #define HRM_I2C &i2cHRM
 #define GPS_UART EV_SERIAL1
+#define GPS_CASIC 1 // handle decoding of 'CASIC' packets from the GPS
 #define HEARTRATE 1
 
 bool pressureBMP280Enabled = false;
@@ -4658,7 +4659,7 @@ bool jswrap_banglejs_idle() {
 bool jswrap_banglejs_gps_character(char ch) {
 #ifdef GPS_PIN_RX
   // if too many chars, roll over since it's probably because we skipped a newline
-  // or messed the message length
+  // or messed up the message length
   if (gpsLineLength >= sizeof(gpsLine)) {
 #ifdef GPS_UBLOX
     if (inComingUbloxProtocol == UBLOX_PROTOCOL_UBX &&
@@ -4689,6 +4690,21 @@ bool jswrap_banglejs_gps_character(char ch) {
   }
 #endif // GPS_UBLOX
   gpsLine[gpsLineLength++] = ch;
+#ifdef GPS_CASIC
+  if (gpsLineLength>2 && gpsLine[0]==0xBA && gpsLine[1]==0xCE) {
+    if (gpsLineLength<4) return true; // not enough data for length
+    int len = gpsLine[2] | (gpsLine[3] << 8);
+    // 4 class, 5 = msg
+    // 4 byte checksum on end
+    if (gpsLineLength>=len+10) { // packet end!
+      memcpy(gpsLastLine, gpsLine, gpsLineLength);
+      gpsLastLineLength = gpsLineLength;
+      bangleTasks |= JSBT_GPS_DATA_LINE;
+      gpsClearLine();
+    }
+    return true;
+  }
+#endif
   if (
 #ifdef GPS_UBLOX
       inComingUbloxProtocol == UBLOX_PROTOCOL_NMEA &&